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Peak planet: Are we starting to consume less?

Some say humanity's ever-rising environmental impact is about to go into reverse. Fact or just fantasy?

By Fred Pearce

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HUMANITY is doomed. Or it was in 1798, when English scholar Robert Malthus published his influential An Essay on the Principle of Population. Malthus predicted that unchecked growth in human numbers would condemn our species to a “perpetual struggle for room and food” and an unbreakable cycle of squalor, famine and disease. Nearly two centuries later, biologist Paul Ehrlich was no less pessimistic. We had exceeded the planet’s “carrying capacity”, he declared in his 1968 bestseller The Population Bomb. “The battle to feed humanity is over. Sometime between 1970 and 1985, the world will undergo vast famines. Hundreds of millions of people are going to starve to death.”

In 2012, our mood has hardly improved. The focus has shifted from how to feed ourselves to our rapacious appetite for energy and raw materials, and the greenhouse gases we pump into the atmosphere to satisfy it. Sooner or later, the argument goes, we must send our planet’s climate and ourselves past the point of no return – if we haven’t done so already.

Might these reports of our imminent demise also be exaggerated? That is the reasoning of those who see a pattern in recent statistics from the industrialised world. People in the US are driving less. Europeans are using less energy. Water use is down in countries such as the US and UK; so is calorie consumption in the UK.

The talk is of “peak stuff”&colon; that beyond a certain level of economic development, people simply stop consuming so much. Technology and the course of economic evolution allow prosperity to keep rising without a linked increase in our use of energy and materials. Our demands on planetary resources stabilise – and ultimately begin to fall.

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Others are unconvinced, seeing in peak stuff a dangerous myth and a thinly veiled excuse to abandon efforts to limit our planetary impact. Without large-scale intervention to curb our excesses now, they argue, peak stuff, if it exists, will be too little, too late. So who is right? Is humanity really about to lose its appetite for stuff – and if so, will it help?

Predictions such as those of Malthus and Ehrlich fell down on a simple point&colon; they failed to see what came next. Malthus missed the industrial revolution and its ways of mass production, which ultimately allowed more people to live longer and more comfortably. Ehrlich failed to factor in the “green revolution”, the widespread use of more productive crop strains and chemical fertilisers and pesticides that has kept food production ahead of the population curve since the 1960s. Perhaps we are missing a similar trend now.

Past predictions of humanity’s doom fell down on a simple point&colon; they didn’t see what came next

Although Ehrlich arrived at the wrong conclusion, his analysis provides a useful framework for assessing arguments about peak stuff. Ehrlich described our planetary footprint as the product of three factors&colon; how many of us there are, how much each of us consumes and how we produce what we consume – that is, the prevailing technology.

Much of our ballooning impact on the planet is down to the first factor, population. Thanks largely to medical advances ensuring that, for the first time in human history, most children get to grow up, our numbers have quadrupled over the past century to seven billion. We are adjusting our behaviour at the same time&colon; women today have 2.5 children on average, half as many as 40 years ago. In much of Europe and east Asia, including China, that number is 1.6 or lower, below the rate needed to maintain population sizes. That leads demographer Joel Cohen of Columbia University in New York to predict that “many of us may live to see population peak in the middle of this century”. If so, that would fulfil the first necessary condition to begin to reduce our demands on the planet.

Not everyone is so sanguine. For a start, even small changes in fertility make a big difference to our numbers over time, and in sub-Saharan Africa fertility rates are still mostly above 4. “African fertility is falling, but more slowly than many of us expected,” says Hania Zlotnik, until recently chief demographer at the United Nations. The UN’s projections for world population in 2100 range from 15.8 billion and rising to 6.2 billion and falling. The middle projection is for a roughly stable 10 billion (see “Peak planet&colon; Population“).

Even if population growth is at the lower end of expectations, reaching peak stuff would still require each of us to consume less – which brings us to Ehrlich’s second metric.

An analysis by Jesse Ausubel and Paul Waggoner of Rockefeller University in New York City suggests that this trend of more economic bang per resource buck is widespread among developing economies, following an initial “cheap and dirty” phase of growth. In 2008, they drew on data covering 1980 to 2006 to argue that there had been “declining intensities of impact, from energy use and carbon emission to food consumption and fertiliser use, globally and in countries ranging from the US and France to China, India, Brazil and Indonesia” (Proceedings of the National Academy of Sciences, vol 105, p 12774). They referred to the trend as economic “dematerialisation”.

That still doesn’t get us near peak stuff&colon; the overall amount we consume has still had to grow to feed economic growth. It is this trend that, by some measures and in some places, might now have reversed.

British environment analyst and author Chris Goodall, for example, argues that people in the UK are consuming no more stuff than they did in the 1990s. According to data from the UK’s Office of National Statistics, he says, the country’s “total material requirement” peaked at 2.17 billion tonnes in 2001 and had fallen by 4 per cent to 2.09 billion tonnes by 2007, even though GDP rose by 18 per cent in that time. “Water use is down, travel and car ownership are down, metals and paper use down, cement use down, calorie consumption and meat eating is falling,” Goodall says.

Water use is down, metals and paper use down, calorie consumption and meat eating are falling

What’s more, between 2000 and 2009, household energy demand fell by almost a tenth across the 27 countries of the European Union; in Sweden, France and the Netherlands, it was down 15 per cent. Water use has also fallen in other countries. US consumption in 2005 was 5 per cent below the peak year of 1980, the US Geological Survey found, although in recent years the trend has been again slightly upwards (see “Peak planet&colon; Water“). In 2010, calorie consumption in the UK was 4 per cent below its 2001 peak, according to a government analysis that reports a “clear picture of longer-term downward trend”. Adam Millard-Ball of McGill University in Montreal, Canada, and the late Lee Schipper of Stanford University in California reported last year that car use has been falling in countries including Germany, the UK, Australia, France and Japan. In the US, car mileage per capita decreased by 5 per cent between 2004 and 2008, according to Robert Puentes and Adie Tomer of the Brookings Institution, a think tank in Washington DC. The young are leading the way&colon; the proportion of US 17-year-olds with a driving licence has fallen from about three-quarters to a half since 1998.

Cultural shifts

Are such apparently dematerialising trends significant, or might factors other than actual reduced consumption explain them? For example, the past few decades have seen the outsourcing of large swathes of manufacturing, with its huge demands on materials, energy and water, from developed economies to lower-wage ones. Metrics such as total material requirement already attempt to take this shift into account, however, and water consumption in the UK has dropped by comparable amounts in private households and in industry. The recession of the past few years has depressed consumption, too, but the downward trajectories were established before it began. And as Millard-Ball and Schipper note, although fuel prices have been rising slowly since 2002, trends such as “peak car” predate the dramatic oil-price fluctuations we have experienced since 2007.

Ausubel suggests instead that the effects of longer-term cultural and economic shifts are beginning to be seen. Beyond a certain level of affluence, he says, we spend proportionally less on resource-intensive staples such as food, housing and clothing, and more on services. For meals in swanky restaurants, for example, much of the cost goes into paying for the skills of the chef and the ambience rather than large quantities of the ingredients. Although the meal creates more economic value, it does not require much more material or energy than food cooked at home.

Similarly, we may use our extra cash to buy better-quality goods that last longer, or make conscious “ecological” choices, often guided by government regulations or something as simple as labelling. Bruno Lapillonne of Enerdata, the agency that compiled the EU energy-use data, says the declining trend can largely be explained by efficiency gains for large electrical appliances and heating systems. As far as peak car is concerned, Richard Florida, an urban studies theorist at the University of Toronto, Canada, suggests that smartphones, social media and internet shopping are substituting for travel, and so owning your own wheels has lost its social cachet for the young (see “Peak planet&colon; Car usage“).

Smartphones, social media and internet shopping mean owning your own wheels has lost its cachet

Such conclusions are disputed. Tim Jackson at the University of Surrey in Guildford, UK, doubts the trends will make a significant difference to our overall consumption, because resource efficiency in one area tends to be cancelled out by increased profligacy elsewhere. In 2009, he and his colleague Nick Hogg showed how digitising the way we receive recorded music has not contributed to dematerialisation, essentially because we buy more hardware to play it on. That hardware might be getting smaller, too, but in total it takes more juice to run. In another sphere Ausubel, although a proponent of dematerialisation, points out that we are driving less but flying more. That leads Julian Allwood, a resource specialist at the University of Cambridge, to say that “the vision of dematerialisation is alluring, but elusive”.

And looking at overall metrics of consumption, such as the amount of carbon dioxide an economy pumps out, it is indeed hard to discern a consistent trend. From 1990 to 2008 the US increased its CO2 emissions by 12 per cent while the EU decreased its by 9 per cent, despite broadly similar economic growth trends (see “Peak planet&colon; Carbon dioxide emissions“). Peak stuff might be part of the story, but it is clearly not all of it.

There is a more basic objection, however&colon; even if peak stuff is reached soon, it will only apply to the billion or so people living in rich countries out of the global population of 7 billion. Achieving worldwide peak stuff, critics argue, would require heading off rising demand in the developing world, while seeing a much more sustained fall in consumption among richer nations. Andrew Simms of the New Economics Foundation, a think tank based in London, points out that the environment does not much care who is doing what where. “Measures of our impact are only meaningful when they are related to the planet’s ability to keep up,” he says.

Take steel, a material that is ubiquitous in modern infrastructure such as homes, offices, cars and factories. Making steel accounts for almost 5 per cent of all CO2 emissions, according to the International Energy Agency. In Europe and North America, steel consumption has plateaued and even declined slightly over the past four decades, but global demand rose by 40 per cent between 2000 and 2010 as the rest of the world played catch-up. Chinese demand for steel nearly quadrupled, hitting 400 kilograms per head per year, a level comparable to that in Europe and North America before the current recession (see “Peak planet&colon; Total steel consumption“). There is potentially plenty more growth to come, with global per-capita steel consumption still only about half that level (see “Peak planet&colon; Steel consumption per capita“).

Critics of peak stuff see that as sufficient grounds to end the discussion. “Evidence of substantial absolute dematerialisation in the rich economies is thin at best,” says Jackson. “At the global level, it is non-existent.” On that reading, worldwide consumption will continue to rise fast, depleting resources and pumping out dangerous levels of greenhouse gases.

Over the years, many attempts have been made to estimate Earth’s “carrying capacity” – that is, how many humans the planet can take, and consuming at what level. The conclusions as to a sustainable population level have varied wildly, from Ehrlich’s 1968 estimate of 1.5 billion to tens of billions. This year, the UK’s Royal Society tried its hand. In a report entitled People and the Planet, it concluded that there is no one right answer&colon; it all depends on technology. And it is here, in the third of Ehrlich’s metrics, that there might be a glimmer of hope for peak stuff.

Technology has always had a hand in determining how many of us can survive on the planet. When humanity turned from hunter-gathering to farming, the world was able to sustain vastly more people because the breeding and cultivation of crops hugely upped the potential food source. Industrial society raised the carrying capacity again by exploiting fossil fuels, not least to produce artificial fertiliser. The problems of overconsumption and resource depletion we face today arguably stem from such innovations. But a further technological revolution might help us use resources more efficiently, without trashing vital ecosystems, and allow billions more to live safely and well.

We might be seeing some positive signs. Countries developing their economies now have access to a range of technologies that can allow them to leapfrog inefficient processes used in developed nations. China has greatly expanded its coal-burning capacity in the past decade, but it has also recently become the world’s largest generator of solar and wind energy. According to figures from the World Bank, the Chinese economy’s carbon intensity – the amount of CO2 emissions relative to the size of economic output – has decreased by almost 70 per cent over the past three decades (see “Peak planet&colon; Carbon dioxide intensity“), and a further 20 per cent reduction from current levels is promised by 2020. If it succeeds, China will have achieved that cut faster than any country at a comparable stage of development.

The carbon intensity of the Chinese economy is falling faster than that of any economy in history

For the world’s most populous country, which recently also became its largest CO2 emitter, that would be a remarkable achievement. And what China can do, other major developing nations such as India, Indonesia and Nigeria can also do.

None of this is certain, Zhou stresses – and we should not sit on our hands and expect China to do our dirty work in cleaning up. Curbing global warming to 2 °C above the average pre-industrial temperature, the generally accepted “safe” level, will probably require carbon emissions to peak within a decade, to be followed by global cuts of more than 50 per cent by mid-century, according to the UN Environment Programme. Even if China limits its emissions to 5 gigatonnes, an ambitious figure, developed countries would need to cut theirs by some 80 per cent to meet that target.

The way we use stuff provides some ways to do that. Allwood points out that more than half of our industrial CO2 emissions come from producing and processing five sorts of stuff&colon; steel, cement, plastic, paper and aluminium. According to the International Energy Agency, energy consumption in the global steel industry could be cut by 34 per cent by adopting proven technologies to save and recycle waste heat and reduce material waste. The paper industry could achieve 38 per cent and cement 40 per cent (see “Peak planet&colon; Waste“).

That still won’t be enough on its own. “Even with the strongest possible assumptions, we cannot hit carbon emissions targets by energy and process efficiency within the existing system,” says Allwood. Jackson puts it more trenchantly&colon;”The idea that the transition to a sustainable economy will emerge spontaneously by giving free rein to markets is patently false,” he says.

One alternative is to switch to using more plant-based materials rather than energy-intensive minerals and hydrocarbons. In April, the US government launched a National Bioeconomy Blueprint, which foresees hugely increased biofuel use and the construction of giant refineries that churn out plastics, fibres and chemicals made by genetically engineered plants. But this is not necessarily a good way to reduce our impact on the planet. It would massively increase the pressure on two other crucial finite resources – land and water – and imply even more use of nitrogen-based fertilisers that acidify soils, upset the natural nitrogen cycle and create dead zones in rivers and oceans.

Or we might let markets decide – but give them the right signals first. In its People and the Planet report, the Royal Society supports the idea of giving cash value to finite “natural capital” just as we do to finite material resources. Through this we would put a price on forests, soils, water supplies and other essential ecological services – an approach that China has been pioneering (see news story). Tinkering with the tax system would also help, says Cameron Hepburn, an economist at the London School of Economics. Switching from income and labour taxes to taxing the use of resources could be a big incentive to change our habits faster and more profoundly in developed economies, where few are in need.

Will we grasp the nettle? The Danish agricultural economist Ester Boserup argued that throughout history, population growth and the pressure of shortages have been necessary spurs to technological developments, which seem to arrive just in time to avert the sort of disasters that exercised the likes of Malthus and Ehrlich. The signs are that we already have the know-how to live long and prosper without demanding ever more from a finite planet. The question is whether we will make the decisions to realise that promise before “just in time” becomes “just too late”.